The S and A switches on a USB charger usually represent different charging modes or current levels. S level is usually a fast charging level, while A level is a slow charging level. In fast charging mode, the charger provides a higher current, which is suitable for situations where a full charge is required quickly; while slow charging mode provides a lower current, which is suitable for battery maintenance or long-term charging.
In addition, the lightning symbol on the USB port usually indicates that it supports power-off charging and fast charging functions.
